Invalid destination folder
Move/API returned 400 Invalid destination folder. (folder id present but not a valid move target).
Why this happens
Wrong id format, not a folder, or not allowed as destination. Sibling Destination folder does not exist means the folder is missing entirely.
Diagnose and fix
1. Refresh the library; choose a real folder you own.
2. Do not move into the same invalid/stale id.
3. See Folders and Folder not found.
4. See Moving folders is not supported yet (Phase 60) if folders were selected for move.